The Peptide Core provides scientists of the Integrin Program Project with pure quantified synthetic peptides as they are requested. Some of the requested peptides are segments of natural proteins; some are isomers of these with scrambled sequences to serve as controls; some peptides are biologically active ligands; some are designed to contain an oligoproline or other region that should act as a framework for presentation of the ligand regions; and some contain novel amino-acid residues specifically synthesized by the Peptide Core for the Integrin Program Project.